A Plagionotus arcuatus ssp. arcuatus darázscincér (Coleoptera: Cerambycidae) fajon belüli kommunikációjának a vizsgálata két, földrajzilag távoli, európai populáción

A bársonyos darázscincér, Plagionotus arcuatus ssp. arcuatus (L.) Európa nagyobb részén gyako- rinak számító szaproxilofág cincér faj, melyet a nyári hónapokban a szabadban tárolt, frissen kivágott tölgyfa alkalmi kártevőjeként tartunk számon. Annak érdekében, hogy azonosítsuk azokat a csalo- gató illatanyagokat, amelyek felhasználhatók a faj rajzáskövetésére, illatanyag gyűjtést végeztünk az imágókból, majd szabadföldi viselkedésvizsgálatokat végeztünk az azonosított illatanyagokkal, melyek a faj lehetséges aggregációs feromon komponensei. Három vegyület, az (R)-3-hidroxihexán- 2-on, az (R)-3-hidroxioktán-2-on, és az (R)-3-hidroxidekán-2-on viszonylag nagy mennyiségben volt jelen a hím kivonatokban Magyarországon és Svédországban egyaránt, függetlenül a filter típusától (aktív szén vagy PorapakTM Q, ezeket a bogarak által kibocsátott illatanyagok megkötésére hasz- náljuk), illetve függetlenül a kivonat készítésére használt oldószer típusától (hexán, dietil éter, vagy diklórmetán). A hidroxi-keton és annak rokon vegyületeinek egyike sem volt kimutatható a nőstények- ből származó kivonatokban. A szabadföldi vizsgálatokban mindkét országban a C6 és a C10 illatanya- gok keveréke, illetve a háromkomponensű keverék csalogatta a legtöbb bogarat. A kontroll csapdák, más kombinációk illetve az önmagukban alkalmazott illatanyagok csalogató hatása nem volt jelen- tős. A hímek és nőstények hasonlóan reagáltak a kezelésekre. Eredményeink azt mutatják, hogy a (R)-3-hidroxihexán-2-on és a (R)-3-hidroxidekán-2-on a bársonyos darázscincér hímek által termelt aggregációs feromon komponensei, míg a (R)-3-hidroxioktán-2-on szerepe nem tisztázott. Az azo- nosított feromonkomponensek a bársonyos darázscincér populáció megfigyelésére alkalmazhatóak

Common Cerambycid Pheromone Components as Attractants for Longhorn Beetles (Cerambycidae) Breeding in Ephemeral Oak Substrates in Northern Europe

Longhorn beetles are ecologically important insects in forest ecosystems as decomposers of woody substrates, microhabitat engineers, and as components of forest food webs. These species can be greatly affected both positively and negatively by modern forestry management practices, and should be monitored accordingly. Through headspace sampling, coupled gas chromatography-electroantennography, gas chromatography-mass spectrometry, and field bioassays, we identified two compounds, 2-methyl-1-butanol and 3-hydroxy-2-hexanone, that constitute aggregation-sex pheromone attractants of three cerambycid species which breed primarily in different types of fresh, recently dead oak wood in Northern Europe: Pyrrhidium sanguineum (L.), Phymatodes alni ssp. alni (L.), and Phymatodes testaceus (L.) (Cerambycinae: Callidiini). Analyses of headspace volatiles collected from live insects indicated that the male-produced aggregation-sex pheromone of P. sanguineum is a 1-15:100 blend of (R)-2-methyl-1-butanol and (R)-3-hydroxy-2-hexanone, whereas the corresponding ratios for P. alni were 70-110:100. In field bioassays, adult P. sanguineum and P. alni were significantly attracted to multiple blends with varying ratios of the two compounds. When tested individually, the compounds were minimally attractive. In contrast, adult P. testaceus exhibited nonspecific attraction to both of the individual compounds and to different blends, despite the hydroxyketone not being part of its pheromone, which consists of (R)-2-methyl-1-butanol alone. Overall, our results suggest that a blend of 50:100 of racemic 2-methyl-1-butanol and 3-hydroxy-2-hexanone is appropriate for parallel, cost-efficient pheromone-based monitoring of all three species. In particular, these species could serve as useful indicators of how modern forestry practices affect a whole guild of saproxylic insects that require ephemeral deadwood substrates for successful breeding

The Male-Produced Aggregation-Sex Pheromone of the Cerambycid Beetle Plagionotus detritus ssp. detritus

The number of longhorn beetles with confirmed aggregation-sex pheromones has increased rapidly in recent years. However, the species that have been studied most intensively are pests, whereas much less is known about the pheromones of longhorn beetles that are rare or threatened. We studied the cerambycid beetle Plagionotus detritus ssp. detritus with the goal of confirming the presence and composition of an aggregation-sex pheromone. This species has suffered widespread population decline due to habitat loss in Western Europe, and it is now considered threatened and near extinction in several countries. Beetles from a captive breeding program in Sweden were used for headspace sampling. Gas chromatography-mass spectrometry revealed that collections from males contained large quantities of two compounds, identified as (R)-3-hydroxy-2-hexanone (major component) and (S)-2-hydroxy-3-octanone (minor component), in addition to smaller quantities of 2,3-hexanedione and 2,3-octanedione. None of the compounds was present in collections from females. When tested singly in a field bioassay, racemic 3-hydroxy-2-hexanone and 2-hydroxy-3-octanone were not attractive to P. detritus, whereas a 5:1 blend elicited significant attraction. Both compounds are known as components of the pheromones of conspecific beetles, but, to our knowledge, this is the first cerambycid shown to use two compounds with different chain lengths, in which the positions of the hydroxyl and carbonyl functions are interchanged between the two. The pheromone has potential as an efficient tool to detect and monitor populations of P. detritus, and may also be useful in more complex studies on the ecology and conservation requirements of this species